Polymorphisms of Thymidylate Synthase in the 5′- and 3′-Untranslated Regions Associated with Risk of Non-Hodgkin’s Lymphoma.

Thymidylate synthase (TS) catalyzes the conversion of dUMP by 5,10-methylenetetrahydrofolate to dTMP in DNA synthesis. Polymorphisms in the untranslated regions(UTRs) of TS, which may modulate TS transcription and expression, have been associated with susceptibility to several malignancies. In this study, to evaluate the association with TS the 28-bp tandem repeat(2R→3R) and the 6-bp deletion(6 bp-) and susceptibility to non-Hodgkin’s lymphoma(NHL), large-scale population-based case-control study was conducted in Chonnam National University Hospital between Mar 1997 and Feb 2006. 553 patients with histologically comfirmed lymphoma and 1,324 controls were evaluated. The cases consisted of 275 diffuse large B-cell lymphomas (DLBCL), 109 T-cell lymphomas and 169 unclassifiable lymphomas. TS 2R2R genotype was significantly associated with increased risk for NHL and T-cell lymphoma, but not for DLBCL. Using subjects with the TS 3R3R as a reference group, the OR of TS 2R2R was 2.00 (95% CI 1.21–3.31, p=0.007) for NHL and 3.30 (95% CI 1.52–7.17, p=0.003) for T-cell lymphoma. The association was 1.65 fold higher and more evident for T-cell lymphoma than NHL. However, there was no significant association of TS 6bp- with NHL.

In conclusion, theses results suggest that TS (2R→3R) may play an important role in the pathogenesis of NHL, and that DNA synthesis may play a crucial roles in the pathogenesis of specific NHL subtypes.